Remains, believed to be those of Chase Deblase, found in Miss.

VANCLEAVE, Miss. (WALA) - Deputies believe they have found the remains belonging to one of two missing Alabama children. The remains, which are believed to be Johnathan Chase Deblase, were found exactly where his father says he dumped him on Highway 57 near Vancleave, Mississippi. Meanwhile, their father, John Deblase appeared before a Mobile County judge.

At 9:00 Wednesday morning, John Deblase pleaded not guilty to aggravated child abuse and abuse of a corpse. At 10:30 a.m., authorities believe they found the remains of his three-year-old son, Johnathan.

"Initially we were told the likelihood of finding anything was slim to none because of the length of time; because of animals out there and because of the terrain," said Richard Deblase, the suspect's father.

Police say the 27-year-old dumped his son's body back in June.

Last week, Deblase told police he put the body in a garbage bag near a wooded area on Highway 57 near Vancleave, Mississippi.

The child was only wearing a diaper.

"Can you imagine what this child thought in his last moments. It had to been horrible," said Jackson County Sheriff Mike Byrd.

Search teams came up with a plan to look for Johnathan Tuesday.

Wednesday morning, they discovered his remains under a pile of sticks.

Late Wednesday afternoon, Deblase's charges were upgraded to murder.

"It's a difficult time for all of us. We all have children. We don't like to see these type things happen," said Chief Tyrone Williams.

Even though police believe they found Johnathan, his sister Natalie is still unaccounted for.

Search teams believe the father dumped her body in North Mobile County.

" We were hoping they would find something. Some traces, somehow so at least we can give them a decent burial. They deserve that, they don't deserve to be out in the woods," said the children's grandfather.

Since the child's body was found in Mississippi, it is possible that Deblase could face charges there as well.

The sheriff says he is reviewing the case with the district attorney.

FOX10 News has learned that the children's stepmother, Heather Leavell-Keaton, will be back in Mobile County Thursday.

The sheriff's office confirms Keaton will be picked up in Kentucky in the morning and will return sometime Thursday.

Keaton is also accused of abusing the children.

For more information on missing and exploited children, click here .